KR100233401B1 - Method for eliminating wiggle noise of disk driving record appartus having a thin-film head - Google Patents

Abstract

end. FIELD OF THE INVENTION The present invention relates to a method for removing wiggle noise in a disc drive recording apparatus having a thin film head.

I. Disclosure of Invention Technical Problem: A disk drive recording apparatus having a thin film head provides a wiggle noise removing method that can shorten the data access time by removing the wiggle noise generated after blocking the recording current without moving the thin film head. Is in.

All. Summary of the Invention Solution of the Invention of Wiggle Noise in a Disk Drive Recording Apparatus with a Thin-Film Head Written Before a Data Sector Contiguous Behind an Errored Servo Sector When a Servo Information Playback Error Occurs due to Wiggle Noise Disabling a disable signal in the data sector section forcibly writes in a predetermined section of the data sector to remove the wiggly noise.

la. Important use of the invention: It can be used for a disk drive recording apparatus having a thin film head.

Description

Wiggle noise elimination method for disk drive recording apparatus having a thin film head {METHOD FOR ELIMINATING WIGGLE NOISE OF DISK DRIVING RECORD APPARTUS HAVING A THIN-FILM HEAD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the removal of wiggle noise in a disc drive recording apparatus having a magnetic thin film head, and more particularly, to a method for removing wiggle noise generated during servo information reproduction of a servo sector after a data recording operation.

Disk drive recording devices such as hard disk drives, floppy disk drives, and the like are widely used as secondary storage devices of computer systems today. Among them, hard disk drives are rapidly expanding due to the advantages of stably storing a large amount of data and accessing data at high speed. Currently, in order to maximize data storage capacity, hard disk drives are increasing the track density (TPI) of the disk, which is a magnetic recording medium, and accordingly, the head is gradually becoming more precise. Currently, the most widely used head as a high precision head is a thin-film head (Thin-Film) to form a core using a semiconductor technology. The use of thin film heads can increase the data recording density, but faces many new problems related to the characteristics of the head poles.

As such, one of the problems related to the characteristics of the head pole is a phenomenon called wiggle noise. This refers to noise generated when the hard disk drive transitions from a data recording operation to a reproduction operation. Hereinafter, the generation process of the wiggle noise will be described in detail with reference to FIGS. 1A and 1B.

FIG. 1A shows the magnetic polarity arrangement state when the write current is applied to the thin film head, and FIG. 1B shows the magnetic polarity arrangement state after the write current interruption is applied. 1A and 1B, reference numeral 2 denotes a coil of a head, 4a and 4b denote poles, and 6 denotes a magnetic layer on a disc. First, in the data writing operation, the recording current according to the recording data is applied to the coil 2 of the head so that the magnetic polarities of the poles 4a and 4b are arranged in a constant direction as shown in Fig. 1A. As a result, a magnetic field is generated, and the magnetic layer 6 on the disk as a recording medium is magnetized by the generated magnetic field, thereby recording data. This data writing process is terminated by cutting off the recording current after writing all the predetermined data. When the recording current is cut off in this way, the arrangement state of the constituent materials of the poles 4a and 4b is disturbed as shown in Fig. 1B, due to the increase in entropy, resulting in a change in the magnetic field. This change in magnetic field is induced in the coil 2 of the head and appears as a current, and this current component is referred to as wiggle noise due to domain pinning.

The problem caused by the generation of the wiggle noise is that it is impossible to reproduce accurate information (servo information or data information) because the residual energy of the recording current is unnecessarily included in the signal to be reproduced after recording the predetermined data. If the amount of wiggle noise is so great that the servo information cannot be reproduced, a problem arises in that the servo control is impossible. In order to solve this problem, a wiggle noise removing process used in a conventional hard disk drive will be described with reference to FIG. 2.

FIG. 2 is a timing diagram of various signals enabled and disabled due to wiggle noise generation in a conventional hard disk drive. In Fig. 2, (a) shows a sector format for a predetermined track on a disc in which servo and data sectors are alternately arranged, and SG is for reproducing the servo information recorded in the servo sector on the track. A servo gate (SGo) signal is enabled, and a fault servo address mark (FSAM) indicates a pulse set when no servo address mark recorded in the servo sector is detected. The SAMW (Servo Address Mark Window (SAMW)) indicates a signal enabled in a predetermined section of the servo sector to detect the servo address mark, and the WF (Wriet Fault: WF) indicates the corresponding servo sector when the servo address mark is not detected. A pulse set at the end of WG (Write Gate: WG) indicates a signal that is enabled for writing predetermined data on the data sector, respectively.

If a wiggle noise occurs when the thin film head (hereinafter referred to as a head) writes predetermined data on the data sector A and then transitions to the servo sector A, the servo address mark is not normally detected within the SAMW section due to the wiggle noise. Accordingly, upon disabling the SAMW, the FSAM is set and input to the control means (not shown) of the drive. At this time, the drive control means sets WF when the FSAM pulse is input, pauses the data recording operation, and repeatedly reproduces the servo information on the servo sector A. If the amount of wiggle noise is excessive and the FSAM is continuously input, the control means moves the head to the parking area (or a preliminary sector prepared for a dummy write area) and then dummy writes on the parking area. Stabilize the magnetization arrangement of. Thereafter, the drive control means moves the head back on the track where the servo sector A exists, and then plays back the servo information recorded on the servo sector A to perform the servo control.

However, the above-described conventional wiggling noise removing method delays the data access time by moving the head to a section (pre-sector, inter-sector PAD) provided to remove the parking area or the wiggling noise at every servo information reproduction error caused by the wiggling noise. Therefore, there was a problem that the overall performance of the drive is reduced.

Accordingly, an object of the present invention is to provide a wiggle noise removal method in a disk drive recording apparatus having a thin film head, which can shorten data access time by removing wiggle noise generated after blocking a recording current without moving the thin film head. .

The present invention for achieving the above object is a wiggle noise removing method of a disk drive recording apparatus comprising a magnetic thin film head, a servo sector in which servo address marks are recorded, and a disk in which data sectors are alternately arranged.

A first step of checking whether a servo information reproduction error occurs due to wiggle noise in the data recording mode;

And a second process of removing the wiggle noise by keeping the write gate signal enabled only in a partial section of the data sector located immediately after the servo sector where the servo information reproducing error occurs when the servo information reproducing error occurs.

1A and 1B are partial cross-sectional views of the head core for explaining the change in the magnetic polarity arrangement state of the poles before and after the write current is cut off;

2 is a timing diagram of various signals enabled and disabled due to wiggle noise generation in a conventional hard disk drive.

3 is a block diagram of a general hard disk drive.

4 is a process flow diagram of a microcontroller 24 for removing wiggle noise in accordance with an embodiment of the present invention.

5 is a timing diagram of various servo control related signals when wiggling noise is removed according to an embodiment of the present invention.

Hereinafter, an operation according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description and drawings many specific details such as head count, sector format and specific processing flow are presented to provide a more general understanding of the invention. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. And detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

Figure 3 shows a block diagram of a general hard disk drive, showing an example of a hard disk drive having two disks 10 and four heads 12 corresponding thereto. Referring to FIG. 2, the disks 10 are typically stacked and mounted on a drive shaft of the spindle motor 36 so that each disk surface corresponds to one head 12. The disk 10 typically consists of a plurality of tracks arranged concentrically and includes a parking zone and a data zone where the head 12 can be located when the drive is not in use (powered off). do. The head 12 is located on the surface of the disk 10 and is mounted to a vertically extending arm 14 of an annular voice coil motor (VCM) 30 arm assembly. The preamplifier 16 preamplifies and applies the reproduction signal picked up by one of the heads 12 to the read / write channel circuit 18 during data reproduction. Encoded write data applied from the read / write channel circuit 18 is driven to drive the corresponding one of the heads 12 to be recorded on the disc 10. At this time, the preamplifier 16 selects one of the heads 12 under the control of a disk data controller (DDC) 38. The read / write channel circuit 18 decodes a reproduction signal applied from the preamplifier 16 to generate read data. The read / write channel circuit 18 encodes write data applied from the DDC 38 to encode a preamplifier ( 16). The read / write channel circuit 18 is applied from the DDC 38. Performs the recording operation and playback operation according to the (Read / Write Bar) signal. In addition, the read / write channel circuit 18 demodulates the head position information which is a part of the servo information recorded on the disk 10 in the data reproducing operation, and generates a position error signal (PES). The PES generated from the read / write channel circuit 18 is applied to the A / D converter 20, and the A / D converter 20 converts the applied PES into a digital step value corresponding to its level so as to provide a microcontroller ( 24) to provide. The gate array 22 reads information (FSAM, etc.) necessary for servo control from the encoded read data (ERD) input from the read / write channel circuit 18, thereby allowing the microcontroller 24 to read. Glue Logic is included to facilitate the interface between the various components while outputting the data. The gate array 22 also masks the write gate input signal WGI input from the DDC 38 and outputs the WG to the read / write channel circuit 18 as WG.

On the other hand, the microcontroller 24 controls the DDC 38 in response to the data recording / reproducing command received from the host computer, and controls the track search and track following. At this time, the microcontroller 24 controls the track tracking by using the PES value input from the A / D converter 20 and generates a pulse DS corresponding to various servo control signals input from the gate array 22. Output The D / A converter 26 converts a control value for position control of the heads 12 generated from the microcontroller 24 into an analog signal and outputs the analog signal. The VCM driver 28 generates a current I (t) for driving the actuator by a signal applied from the D / A converter 26 and applies it to the VCM 30. The VCM 30 located on the other side of the actuator having the heads 12 attached to one side moves the heads 12 horizontally on the disk 10 in response to the current direction and current level input from the VCM driver 28. Let's do it. The motor controller 32 controls the spindle motor driver 34 according to a control value for rotation control of the disks 10 generated from the microcontroller 24. The spindle motor driver 34 rotates the disks 10 by driving the spindle motor 36 under the control of the motor controller 32. On the other hand, the DDC 38 manages most of the digital portion of the data channel in the hard disk drive. The main functions include a data interface with a host computer, management of a data recording format recorded on the disk 10, and buffer memory (40). It performs functions such as error correction for management and playback data. The DDC 38 also responds to the input of Data Sector (DS) pulses DS and WF from the microcontroller 24. A signal is generated and output to the read / write channel circuit 18. The buffer memory 40 connected to the DDC 38 temporarily stores data transferred between the disk 10 and the host computer under the control of the DDC 38.

4 is a flowchart illustrating a process of the microcontroller 24 for removing wiggle noise according to an embodiment of the present invention, and FIG. 5 is a diagram illustrating various servo control related signals during wiggle noise removal according to an embodiment of the present invention. A timing diagram is shown. Hereinafter, an operation according to an embodiment of the present invention will be described in detail with reference to FIGS. 3 to 5.

First, in response to receiving a data recording command from the host computer, the microcontroller 24 places the head 12 on the target track in response to the data recording command. A pulse DS is generated and output to the DDC 38. As a result, the DDC 38 performs an operation on the data sector A section. By outputting the signal at the "low" level, predetermined data received from the host computer is recorded in the data sector A section. Thereafter, in step 52, the microcontroller 24 checks whether the servo sector A section is applied, and checks whether the FSAM is input from the gate array 22 in the servo sector A section. If the Wiggle noise is severely generated due to the blocking of the recording current applied to the head 12 to record predetermined data in the Data Sector A section, the servo address mark of the Servo Sector A section is SAMW due to the Wiggle noise. It will be missed in the enable interval. Accordingly, when the FSAM is set and input at the time when the SAMW of the servo sector A section is disabled, the microcontroller 24 reproduces the servo information reproduced from the servo sector located at the data sector A potential in step 56 regardless of the FSAM. Perform servo control using. Thereafter, in step 58, the microcontroller 24 generates a data sector pulse DS at the time of disabling the SG, outputs the data sector pulse DS to the DDC 38, and proceeds to step 60. A predetermined write current is applied to the head 12 by the data sector pulse DS output in step 58, and the head 12 is positioned on the data sector B section. That is, the magnetization arrangement state of the head 12 in an unstable state can be restored to a stable state by writing to the data sector predetermined section with a predetermined write current applied to the head 12 located on the data sector B section. do.

On the other hand, in step 60, the microcontroller 24 sets the WF after a predetermined time elapses after the data sector pulse DS is generated. As a result, as shown in FIG. The signal is applied to the read / write channel circuit 18 at the "high" level. As a result, the write current applied to the head 12 in the data sector B section is cut off, and the drive mode is switched to the data reproduction mode. After that, the microcontroller 24 checks whether the servo sector B section is performed in step 62, proceeds to step 64 in the case of the servo sector B section, plays back the servo information, and performs servo control using the servo information reproduced in step 66. Return to the main servo control flow.

That is, according to the present invention, the microcontroller 24 performs smooth servo control by completely removing the wiggle noise generated when the transition from the data recording mode to the servo information reproducing mode is performed on the data sector existing behind the servo sector to be reproduced. You can do it.

As described above, the present invention has the advantage that the performance of the drive can be improved by shortening the delay of data access time due to the movement of the thin film head by efficiently eliminating the wiggle noise generated after the recording current is cut off without moving the thin film head. have.

Claims (7)

A wiggle noise removing method of a disc drive recording apparatus comprising a magnetic thin film head, a disc in which a servo sector in which a servo address mark is recorded, and a disc in which data sectors are alternately arranged; A first step of checking whether a servo information reproduction error occurs due to wiggle noise in the data recording mode; Wiggle noise, characterized in that the second step of removing the wiggle noise by keeping the light gate signal enabled only in a section of the data sector located immediately after the servo sector where the servo information reproducing error occurs when the servo information reproducing error occurs How to remove. The method of claim 1, wherein the write gate signal is enabled from the head of the data sector. 2. The method of claim 1, wherein the enabled light gate signal is disabled by a write fault signal that is set after a predetermined time elapses from the end of the servo sector when the servo address mark is not detected. The wiggle of claim 1, further comprising performing a servo control by using the servo information reproduced from a servo sector existing at a potential servo sector potential when the servo information reproduction error occurs due to the wiggly noise. How to remove noise. A hard disk drive comprising a magnetic thin film head and a disk in which a plurality of servo sectors and data sectors are alternately arranged on the same track. A first step of checking whether a servo information playback error occurs when the servo information playback mode transitions from the data recording mode; When the servo information regeneration error occurs, the servo control is performed using the servo information reproduced from the previous servo sector, and the write gate signal is written so that arbitrary data is written to a part of the data sector located immediately after the servo sector generated by the servo information regeneration error. Wiggle noise removing method characterized in that the second process to enable. 6. The method of claim 5, wherein the write gate signal is enabled from the head of the data sector. 7. The method of claim 6, wherein the light gate signal in the enabled state is disabled by a write fault signal set after a predetermined time when the servo address mark is not detected.